Starch sugars mainly containing G3 to G5 are widely applied in pharmaceutical, healthcare and food industry areas. G3 and G5 refer to the glucose units. By way of example, G3 refers to sugar that is composed of three Glucose units linked together as one component. Chinese Patent 96196047.7 introduced a method to depress the bacteria in the starch sugar compound. Starch sugars mainly containing G3 to G5 can be obtained by organic chemistry synthesis from monosaccharide and disaccharide, or by degradation of natural starch, glycolipide and glycopeptide. Other processes are also known. By way of example, Chinese patent 99117102.0 provides an enzymatic degradation process to make oligosaccharide. The oligosaccharide was obtained from the degradation of polysaccharide in plants. Chinese Patent 01109692.6 introduced a method to make oligosaccharide with Bifido Factor from root nodule.
Currently, the enzymatic hydrolysis method is the main process. It is based on starch as raw material for the industrial production of starch sugars mainly containing G3 to G5. The process is comprised of two steps. The first step is to get the maltose syrup through starch hydrolysis with α-amylases. The second step is to get the target product through transglucosylation with the co-reaction of α-amylases and α-glucosidase, and then the routine filtration, decolouration, desalting and concentration process procedures are applied to get the final product.
The processing procedure is as follows:

The content of G3 to G5 in the final product from the process described above is about 50% to 60%. The other main compounds are glucose and maltose which make up about 50% of the final product. The health benefits in the product are contributed by G3 to G5. A lot of glucose and maltose exist in the final product which can disturb the main two health benefits of the product. One of the main health benefits is the proliferation of beneficial microbiota bifidobacteria species in the gastrointestinal tract of humans, and the other main health benefit is the anti-dental caries function. As a result, the health benefits and commercial value of the product are significantly reduced.